SSJ  3.3.1
Stochastic Simulation in Java
Public Member Functions | Static Public Member Functions | List of all members
UniformDist Class Reference

Extends the class ContinuousDistribution for the uniform distribution [100]  (page 276) over the interval \([a,b]\). More...

Inheritance diagram for UniformDist:
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Collaboration diagram for UniformDist:
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Public Member Functions

 UniformDist ()
 Constructs a uniform distribution over the interval \((a,b) = (0,1)\).
 
 UniformDist (double a, double b)
 Constructs a uniform distribution over the interval \((a,b)\).
 
double density (double x)
 
double cdf (double x)
 Returns the distribution function \(F(x)\). More...
 
double barF (double x)
 Returns \(\bar{F}(x) = 1 - F(x)\). More...
 
double inverseF (double u)
 Returns the inverse distribution function \(F^{-1}(u)\), defined in ( inverseF ). More...
 
double getMean ()
 Returns the mean of the distribution function.
 
double getVariance ()
 Returns the variance of the distribution function.
 
double getStandardDeviation ()
 Returns the standard deviation of the distribution function.
 
double getA ()
 Returns the parameter \(a\).
 
double getB ()
 Returns the parameter \(b\).
 
void setParams (double a, double b)
 Sets the parameters \(a\) and \(b\) for this object.
 
double [] getParams ()
 Return a table containing the parameters of the current distribution. More...
 
String toString ()
 Returns a String containing information about the current distribution.
 
- Public Member Functions inherited from ContinuousDistribution
abstract double density (double x)
 Returns \(f(x)\), the density evaluated at \(x\). More...
 
double barF (double x)
 Returns the complementary distribution function. More...
 
double inverseBrent (double a, double b, double u, double tol)
 Computes the inverse distribution function \(x = F^{-1}(u)\), using the Brent-Dekker method. More...
 
double inverseBisection (double u)
 Computes and returns the inverse distribution function \(x = F^{-1}(u)\), using bisection. More...
 
double inverseF (double u)
 Returns the inverse distribution function \(x = F^{-1}(u)\). More...
 
double getMean ()
 Returns the mean. More...
 
double getVariance ()
 Returns the variance. More...
 
double getStandardDeviation ()
 Returns the standard deviation. More...
 
double getXinf ()
 Returns \(x_a\) such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\). More...
 
double getXsup ()
 Returns \(x_b\) such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\). More...
 
void setXinf (double xa)
 Sets the value \(x_a=\) xa, such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\). More...
 
void setXsup (double xb)
 Sets the value \(x_b=\) xb, such that the probability density is 0 everywhere outside the interval \([x_a, x_b]\). More...
 

Static Public Member Functions

static double density (double a, double b, double x)
 Computes the uniform density function \(f(x)\) in ( funiform ).
 
static double cdf (double a, double b, double x)
 Computes the uniform distribution function as in ( cdfuniform ).
 
static double barF (double a, double b, double x)
 Computes the uniform complementary distribution function \(\bar{F}(x)\).
 
static double inverseF (double a, double b, double u)
 Computes the inverse of the uniform distribution function ( cdinvfuniform ).
 
static double [] getMLE (double[] x, int n)
 Estimates the parameter \((a, b)\) of the uniform distribution using the maximum likelihood method, from the \(n\) observations \(x[i]\), \(i = 0, 1, …, n-1\). More...
 
static UniformDist getInstanceFromMLE (double[] x, int n)
 Creates a new instance of a uniform distribution with parameters \(a\) and \(b\) estimated using the maximum likelihood method based on the \(n\) observations \(x[i]\), \(i = 0, 1, …, n-1\). More...
 
static double getMean (double a, double b)
 Computes and returns the mean \(E[X] = (a + b)/2\) of the uniform distribution with parameters \(a\) and \(b\). More...
 
static double getVariance (double a, double b)
 Computes and returns the variance \(\mbox{Var}[X] = (b - a)^2/12\) of the uniform distribution with parameters \(a\) and \(b\). More...
 
static double getStandardDeviation (double a, double b)
 Computes and returns the standard deviation of the uniform distribution with parameters \(a\) and \(b\). More...
 

Additional Inherited Members

- Public Attributes inherited from ContinuousDistribution
int decPrec = 15
 
- Protected Attributes inherited from ContinuousDistribution
double supportA = Double.NEGATIVE_INFINITY
 
double supportB = Double.POSITIVE_INFINITY
 
- Static Protected Attributes inherited from ContinuousDistribution
static final double XBIG = 100.0
 
static final double XBIGM = 1000.0
 
static final double [] EPSARRAY
 

Detailed Description

Extends the class ContinuousDistribution for the uniform distribution [100]  (page 276) over the interval \([a,b]\).

Its density is

\[ f(x) = 1/(b-a) \qquad\mbox{ for } a\le x\le b \tag{funiform} \]

and 0 elsewhere. The distribution function is

\[ F(x) = (x-a)/(b-a) \qquad\mbox{ for } a\le x\le b \tag{cdfuniform} \]

and its inverse is

\[ F^{-1}(u) = a + (b - a)u \qquad\mbox{for }0 \le u \le1. \tag{cdinvfuniform} \]

Member Function Documentation

◆ barF()

double barF ( double  x)

Returns \(\bar{F}(x) = 1 - F(x)\).

Parameters
xvalue at which the complementary distribution function is evaluated
Returns
complementary distribution function evaluated at x

Implements Distribution.

◆ cdf()

double cdf ( double  x)

Returns the distribution function \(F(x)\).

Parameters
xvalue at which the distribution function is evaluated
Returns
distribution function evaluated at x

Implements Distribution.

◆ getInstanceFromMLE()

static UniformDist getInstanceFromMLE ( double []  x,
int  n 
)
static

Creates a new instance of a uniform distribution with parameters \(a\) and \(b\) estimated using the maximum likelihood method based on the \(n\) observations \(x[i]\), \(i = 0, 1, …, n-1\).

Parameters
xthe list of observations to use to evaluate parameters
nthe number of observations to use to evaluate parameters

◆ getMean()

static double getMean ( double  a,
double  b 
)
static

Computes and returns the mean \(E[X] = (a + b)/2\) of the uniform distribution with parameters \(a\) and \(b\).

Returns
the mean of the uniform distribution \(E[X] = (a + b) / 2\)

◆ getMLE()

static double [] getMLE ( double []  x,
int  n 
)
static

Estimates the parameter \((a, b)\) of the uniform distribution using the maximum likelihood method, from the \(n\) observations \(x[i]\), \(i = 0, 1, …, n-1\).

The estimates are returned in a two-element array, in regular order: [ \(a\), \(b\)]. The maximum likelihood estimators are the values \((\hat{a}\), \(\hat{b})\) that satisfy the equations

\begin{align*} \hat{a} & = \min_i \{x_i\} \\ \hat{b} & = \max_i \{x_i\}. \end{align*}

See [118]  (page 300).

Parameters
xthe list of observations used to evaluate parameters
nthe number of observations used to evaluate parameters
Returns
returns the parameters [ \(\hat{a}\), \(\hat{b}\)]

◆ getParams()

double [] getParams ( )

Return a table containing the parameters of the current distribution.

This table is put in regular order: [ \(a\), \(b\)].

Implements Distribution.

◆ getStandardDeviation()

static double getStandardDeviation ( double  a,
double  b 
)
static

Computes and returns the standard deviation of the uniform distribution with parameters \(a\) and \(b\).

Returns
the standard deviation of the uniform distribution

◆ getVariance()

static double getVariance ( double  a,
double  b 
)
static

Computes and returns the variance \(\mbox{Var}[X] = (b - a)^2/12\) of the uniform distribution with parameters \(a\) and \(b\).

Returns
the variance of the uniform distribution \(\mbox{Var}[X] = (b - a)^2 / 12\)

◆ inverseF()

double inverseF ( double  u)

Returns the inverse distribution function \(F^{-1}(u)\), defined in ( inverseF ).

Parameters
uvalue in the interval \((0,1)\) for which the inverse distribution function is evaluated
Returns
the inverse distribution function evaluated at u

Implements Distribution.


The documentation for this class was generated from the following file: